Theo Todman's Web Page - Notes Pages

Personal Identity

Brain

(Text as at 18/08/2009 20:39:50)

*** THIS IS NOT THE LATEST VERSION OF THIS NOTE ***

There is a view that we¹ are really, most fundamentally, our brains. It seems to promise some good things from both the “psychological² criterion” and “bodily³ criterion” camps, since the brain is indeed part of the body⁴, and, in the absence of a soul⁵, the source of all our psychological functions. However, we seem to be much more than our brains. After all, who would want to be a BIV⁶ (Brain in a Vat)? According to Johnston (see "Johnston (Mark) - Human Beings"), BIVs are “maximally mutilated” human beings; which seems to be along the right lines. Note the important distinction between your surviving in a maximally mutilated state (as a brain) and you “really” being your brain.

This is an issue the Animalist has to contend with - whether a BIV is an animal. Snowdon claims (where⁷?) that no-one seems to think this, a view that Olson shares but on which he may be open to objection. He says that an animal with a prosthetic leg is a smaller animal with something non-animal attached. If this is admitted, don’t we end up with a sorites argument, that a BIV is a (very much) smaller animal; though not, I think, with any paradox?

The big question is whether an animal’s brain is just another organ (like its liver) or whether it has some other status. That it is somehow special can be presupposed if we start conceptually with the brain as the core from which other parts are shaved off. Whether this is the right approach depends, I think, on what the brain does for the animal, and where the animal is on the phylogenetic tree. The brain is a much more important organ in some animals than others; in some lower animals it has no psychological functions and (maybe) its regulatory functions aren’t essential (I need to check⁸ this).

Why is the Woody Allen expostulation about his brain (in Sleeper) “(is) my second favourite organ” amusing? Firstly, of course, because of the sexual innuendo and the ultimately strange prioritisation (since you can’t enjoy sexual excitement without a brain), but also, I think, because your brain isn’t an organ that you “have”. Without your brain, there’s no “you” at all, or at least this is a strong intuition.

You can obviously (given even today’s technology), do without a liver, and it seems that on a life-support machine your body can do without its brain – where the brain is looked upon merely as a regulator. But the reference of “you” is a bit slippery in these contexts. There is a sense in which you as an organism can do without a brain – on life support – but “you” as an essentially psychological being cannot. The animalists claim that you – being identical to an animal – have no essential psychological predicates; yet it is difficult to resist the intuition that there’s a reference of “you” that does have essential psychological predicates. This is to you as a person – but the big question is whether this person is a separate substance constituted by the human animal, or is just a way of describing the animal when possessed of the appropriate psychological predicates. Saying that you can’t do without your brain is just another way of saying that your psychological predicates are those most important to you (the animal); those without which the other predicates cannot be enjoyed.

The issue fundamentally concerns the integrity of organisms⁹. It is said that a brain isn’t an organism; but does an organism have to be self-supporting (the main reason for denying the status of organisms to disembodied brains)? After all, we seem to be allowing that an organism on life support is correctly described as an organism. We’ll discuss this further in its place.

These issues are especially important when we consider various Thought Experiments¹⁰, in particular Brain Transplants¹¹. Transplantation¹² of all sorts seems to involve fusion¹³, with its logical problems for identity¹⁴ (not just for persons).